How does this Key Tronic mouse work?

[textadventurer]

No idea what this mechanism is. Anybody know?

image_2023-09-25_092629158.png (2.48 MiB) Viewed 32490 times

image_2023-09-25_092644839.png (2.32 MiB) Viewed 32490 times

[Muirium]

The cable’s regular serial, right? Plug it in and give it a shot. Wonder how it compares to the ball mice of the era.

[textadventurer]

It's not mine, a keyboard seller mentioned he has these and sent me the pics. I'm not interested in mice, but woud pick it up if it had any historical value. But I mostly wonder how this mouse works!

[jsheradin]

It's a pretty cool mechanism!

Jump to about 2:22 for the quick explanation.

[Findecanor]

The wheels are tilted, so that one touches the surface vertically and the other horizontally. The video shows it quite well. It is like Engelbart's original mechanism, only lower-profile.

The problem is that the horizontal wheel resist vertical motion and vice versa, giving the mouse a different centre if you move it vertically vs horizontally.
DEC's circular mouse with this mechanism and a circular shape was awful. If you tried to move it in one direction, the resistance from the other wheel made it rotate in your hand and with the shape being circular, you lost the direction easily. If you thought the Apple iMac mouse was bad, you know nothing ...

[textadventurer]

Oof, sounds hard to work with. Thanks for the info and movie! It's a novelty I don't think I will use for more than 5 minutes, so I'll leave it with the seller